perf: SIMD heightfield math and zone idle throttling

compose.yml

@@ -104,6 +104,8 @@ services:
     environment:
       GameRoot: ${GAME_ROOT}
       DistributedTransactions: ${DISTRIBUTED_TRANSACTIONS}
+      # .NET 8 DATAS: dynamically scales GC heaps to reduce idle memory usage
+      DOTNET_GCDynamicAdaptationMode: 1
     depends_on:
       migration:
         condition: service_completed_successfully

src/Perpetuum.Tests/Unit/CompactPassabilityMaskTests.cs

@@ -0,0 +1,58 @@
+using Perpetuum.Zones.Terrains;
+using Xunit;
+
+namespace Perpetuum.Tests.Unit
+{
+    public class CompactPassabilityMaskTests
+    {
+        [Fact]
+        public void Bitmask_get_set_and_bounds()
+        {
+            var mask = new CompactPassabilityMask(64, 64);
+
+            // Default is false (0)
+            Assert.False(mask.IsWalkable(0, 0));
+            Assert.False(mask.IsWalkable(10, 10));
+
+            // Set some bits
+            mask.SetWalkable(0, 0, true);
+            mask.SetWalkable(15, 20, true);
+            mask.SetWalkable(31, 31, true);
+            mask.SetWalkable(32, 31, true); // cross 32-bit boundary
+            mask.SetWalkable(63, 63, true);
+
+            Assert.True(mask.IsWalkable(0, 0));
+            Assert.True(mask.IsWalkable(15, 20));
+            Assert.True(mask.IsWalkable(31, 31));
+            Assert.True(mask.IsWalkable(32, 31));
+            Assert.True(mask.IsWalkable(63, 63));
+
+            // Unset a bit
+            mask.SetWalkable(15, 20, false);
+            Assert.False(mask.IsWalkable(15, 20));
+            Assert.True(mask.IsWalkable(0, 0));
+
+            // Out of bounds
+            Assert.False(mask.IsWalkable(-1, 0));
+            Assert.False(mask.IsWalkable(0, -1));
+            Assert.False(mask.IsWalkable(64, 0));
+            Assert.False(mask.IsWalkable(0, 64));
+        }
+
+        [Fact]
+        public void SetAll_fills_entire_grid()
+        {
+            var mask = new CompactPassabilityMask(100, 100);
+            mask.SetAll(true);
+
+            Assert.True(mask.IsWalkable(0, 0));
+            Assert.True(mask.IsWalkable(50, 50));
+            Assert.True(mask.IsWalkable(99, 99));
+
+            mask.SetAll(false);
+            Assert.False(mask.IsWalkable(0, 0));
+            Assert.False(mask.IsWalkable(50, 50));
+            Assert.False(mask.IsWalkable(99, 99));
+        }
+    }
+}

src/Perpetuum.Tests/Unit/HeightfieldMetadataTests.cs

@@ -0,0 +1,264 @@
+using Perpetuum.Zones.Terrains;
+using Xunit;
+
+namespace Perpetuum.Tests.Unit
+{
+    public class HeightfieldMetadataTests
+    {
+        [Fact]
+        public void Chunk_bounds_and_ray_above_chunk_queries()
+        {
+            var rawData = new ushort[64 * 64];
+            var altLayer = new AltitudeLayer(rawData, 64, 64);
+
+            // Fill a chunk (0,0 to 15,15) with height 10.0 (raw: 10 * 32 = 320)
+            for (int y = 0; y < 16; y++)
+            {
+                for (int x = 0; x < 16; x++)
+                {
+                    altLayer[x, y] = (ushort)(10 * 32);
+                }
+            }
+
+            // Fill another chunk (16,0 to 31,15) with height 50.0 (raw: 50 * 32 = 1600)
+            for (int y = 0; y < 16; y++)
+            {
+                for (int x = 16; x < 32; x++)
+                {
+                    altLayer[x, y] = (ushort)(50 * 32);
+                }
+            }
+
+            var metadata = HeightfieldMetadata.ExtractFrom(altLayer, null, chunkSize: 16);
+
+            Assert.Equal(4, metadata.ChunksX);
+            Assert.Equal(4, metadata.ChunksY);
+
+            // Chunk (0,0) has max height 10.0
+            metadata.GetChunkBounds(0, 0, out float min0, out float max0);
+            Assert.Equal(10.0f, min0);
+            Assert.Equal(10.0f, max0);
+
+            // Chunk (1,0) has max height 50.0
+            metadata.GetChunkBounds(1, 0, out float min1, out float max1);
+            Assert.Equal(50.0f, min1);
+            Assert.Equal(50.0f, max1);
+
+            // Ray at Z=20 is strictly above chunk (0,0), but NOT above chunk (1,0)
+            Assert.True(metadata.CanRayPassAboveChunk(0, 0, rayMinZ: 20.0f));
+            Assert.False(metadata.CanRayPassAboveChunk(1, 0, rayMinZ: 20.0f));
+
+            // Ray at Z=60 is above both
+            Assert.True(metadata.CanRayPassAboveChunk(0, 0, rayMinZ: 60.0f));
+            Assert.True(metadata.CanRayPassAboveChunk(1, 0, rayMinZ: 60.0f));
+        }
+
+        [Fact]
+        public void Coordinates_mapping()
+        {
+            var metadata = new HeightfieldMetadata(2048, 2048, chunkSize: 16);
+            Assert.Equal(128, metadata.ChunksX);
+            Assert.Equal(128, metadata.ChunksY);
+
+            metadata.GetChunkCoordinates(0, 0, out int cx0, out int cy0);
+            Assert.Equal(0, cx0);
+            Assert.Equal(0, cy0);
+
+            metadata.GetChunkCoordinates(15, 15, out int cx1, out int cy1);
+            Assert.Equal(0, cx1);
+            Assert.Equal(0, cy1);
+
+            metadata.GetChunkCoordinates(16, 32, out int cx2, out int cy2);
+            Assert.Equal(1, cx2);
+            Assert.Equal(2, cy2);
+
+            metadata.GetChunkCoordinates(2047, 2047, out int cx3, out int cy3);
+            Assert.Equal(127, cx3);
+            Assert.Equal(127, cy3);
+        }
+
+        [Fact]
+        public void Mark_dirty_tile_flags_only_its_chunk_and_deduplicates()
+        {
+            var metadata = new HeightfieldMetadata(64, 64, chunkSize: 16);
+
+            Assert.False(metadata.HasDirtyChunks);
+
+            metadata.MarkDirtyTile(5, 5);
+            Assert.Equal(1, metadata.DirtyChunkCount);
+
+            // Same chunk again: no double count.
+            metadata.MarkDirtyTile(15, 15);
+            Assert.Equal(1, metadata.DirtyChunkCount);
+
+            // Different chunk.
+            metadata.MarkDirtyTile(20, 20);
+            Assert.Equal(2, metadata.DirtyChunkCount);
+
+            // Out of bounds: ignored.
+            metadata.MarkDirtyTile(-1, 0);
+            metadata.MarkDirtyTile(64, 0);
+            metadata.MarkDirtyTile(0, -5);
+            metadata.MarkDirtyTile(0, 100);
+            Assert.Equal(2, metadata.DirtyChunkCount);
+        }
+
+        [Fact]
+        public void Mark_dirty_area_covers_exactly_the_intersecting_chunks()
+        {
+            var metadata = new HeightfieldMetadata(64, 64, chunkSize: 16);
+
+            // Area spanning chunks (0,0), (1,0), (0,1), (1,1) and clipping chunk (2,0)/(0,2).
+            metadata.MarkDirtyArea(new Area(10, 10, 37, 37));
+            Assert.Equal(9, metadata.DirtyChunkCount);
+
+            // Fully outside: ignored.
+            metadata.MarkDirtyArea(new Area(100, 100, 110, 110));
+            metadata.MarkDirtyArea(new Area(-50, -50, -10, -10));
+            Assert.Equal(9, metadata.DirtyChunkCount);
+
+            // Negative area that still intersects the map: clamped, no out-of-range chunks.
+            var clamped = new HeightfieldMetadata(64, 64, chunkSize: 16);
+            clamped.MarkDirtyArea(new Area(-30, -30, 5, 5));
+            Assert.Equal(1, clamped.DirtyChunkCount);
+
+            // Fully outside (all negative): ignored.
+            clamped.MarkDirtyArea(new Area(-30, -30, -1, -1));
+            Assert.Equal(1, clamped.DirtyChunkCount);
+
+            // Area beyond the edge: clamped to the last chunk row/column.
+            var edge = new HeightfieldMetadata(64, 64, chunkSize: 16);
+            edge.MarkDirtyArea(new Area(60, 60, 200, 200));
+            Assert.Equal(1, edge.DirtyChunkCount);
+            edge.GetChunkBounds(3, 3, out float min, out float max);
+            Assert.Equal(0f, min);
+        }
+
+        [Fact]
+        public void Recompute_dirty_rebakes_only_flagged_chunks_and_clears_the_flags()
+        {
+            var rawData = new ushort[64 * 64];
+            var altLayer = new AltitudeLayer(rawData, 64, 64);
+            for (int y = 0; y < 64; y++)
+            {
+                for (int x = 0; x < 64; x++)
+                {
+                    altLayer[x, y] = (ushort)(10 * 32);
+                }
+            }
+
+            var metadata = HeightfieldMetadata.ExtractFrom(altLayer, null, chunkSize: 16);
+            Assert.False(metadata.HasDirtyChunks);
+            Assert.Equal(0, metadata.RecomputeDirty(altLayer));
+
+            // Raise one tile in chunk (0,0) and mark it.
+            altLayer[5, 5] = (ushort)(100 * 32);
+            metadata.MarkDirtyTile(5, 5);
+            Assert.Equal(1, metadata.DirtyChunkCount);
+
+            // Until the re-bake the chunk bound is stale.
+            metadata.GetChunkBounds(0, 0, out _, out float staleMax);
+            Assert.Equal(10f, staleMax);
+
+            int rebaked = metadata.RecomputeDirty(altLayer);
+            Assert.Equal(1, rebaked);
+            Assert.False(metadata.HasDirtyChunks);
+
+            metadata.GetChunkBounds(0, 0, out float min, out float max);
+            Assert.Equal(10f, min);
+            Assert.Equal(100f, max);
+
+            // Untouched chunks keep their bounds and nothing is re-baked on a second drain.
+            metadata.GetChunkBounds(1, 0, out _, out float otherMax);
+            Assert.Equal(10f, otherMax);
+            Assert.Equal(0, metadata.RecomputeDirty(altLayer));
+        }
+
+        [Fact]
+        public void Plant_blocking_height_is_picked_up_by_dirty_recompute()
+        {
+            var rawData = new ushort[64 * 64];
+            var altLayer = new AltitudeLayer(rawData, 64, 64);
+            for (int y = 0; y < 64; y++)
+            {
+                for (int x = 0; x < 64; x++)
+                {
+                    altLayer[x, y] = (ushort)(10 * 32);
+                }
+            }
+
+            var blockLayer = new Layer<BlockingInfo>(LayerType.Blocks, 64, 64);
+            var metadata = HeightfieldMetadata.ExtractFrom(altLayer, blockLayer, chunkSize: 16);
+
+            metadata.GetChunkBounds(2, 2, out _, out float before);
+            Assert.Equal(10f, before);
+
+            // A plant grows on tile (40, 40) (chunk (2,2)) with blocking height 15, the way
+            // NatureCube commits it: a single SetArea over the scanned cube.
+            blockLayer[40, 40] = new BlockingInfo(BlockingFlags.Plant, 15);
+            metadata.MarkDirtyArea(new Area(32, 32, 47, 47));
+            Assert.Equal(1, metadata.DirtyChunkCount);
+
+            metadata.RecomputeDirty(altLayer, blockLayer);
+
+            metadata.GetChunkBounds(2, 2, out float min, out float max);
+            Assert.Equal(10f, min);
+            Assert.Equal(25f, max);
+
+            // The plant wilts: the same area is re-scanned with no blocking height.
+            blockLayer[40, 40] = BlockingInfo.None;
+            metadata.MarkDirtyArea(new Area(32, 32, 47, 47));
+            metadata.RecomputeDirty(altLayer, blockLayer);
+
+            metadata.GetChunkBounds(2, 2, out _, out float after);
+            Assert.Equal(10f, after);
+        }
+
+        [Fact]
+        public void Global_max_height_tracks_full_and_incremental_rebakes()
+        {
+            var rawData = new ushort[64 * 64];
+            var altLayer = new AltitudeLayer(rawData, 64, 64);
+            for (int y = 0; y < 64; y++)
+            {
+                for (int x = 0; x < 64; x++)
+                {
+                    altLayer[x, y] = (ushort)(10 * 32);
+                }
+            }
+
+            var metadata = HeightfieldMetadata.ExtractFrom(altLayer, null, chunkSize: 16);
+            Assert.Equal(10f, metadata.GlobalMaxHeight);
+
+            // Raise one tile, re-bake incrementally: the global max follows it up...
+            altLayer[5, 5] = (ushort)(100 * 32);
+            metadata.MarkDirtyTile(5, 5);
+            metadata.RecomputeDirty(altLayer);
+            Assert.Equal(100f, metadata.GlobalMaxHeight);
+
+            // ...and back down when the tile is levelled again.
+            altLayer[5, 5] = (ushort)(10 * 32);
+            metadata.MarkDirtyTile(5, 5);
+            metadata.RecomputeDirty(altLayer);
+            Assert.Equal(10f, metadata.GlobalMaxHeight);
+        }
+
+        [Fact]
+        public void Recompute_all_clears_dirty_flags()
+        {
+            var rawData = new ushort[64 * 64];
+            var altLayer = new AltitudeLayer(rawData, 64, 64);
+            var metadata = HeightfieldMetadata.ExtractFrom(altLayer, null, chunkSize: 16);
+
+            metadata.MarkDirtyTile(0, 0);
+            metadata.MarkDirtyTile(63, 63);
+            Assert.Equal(2, metadata.DirtyChunkCount);
+
+            metadata.RecomputeAll(altLayer);
+
+            Assert.False(metadata.HasDirtyChunks);
+            Assert.Equal(0, metadata.DirtyChunkCount);
+            Assert.Equal(0, metadata.RecomputeDirty(altLayer));
+        }
+    }
+}